This invention relates to the field of integrated circuits; and, more particularly, to low cost, high voltage power field effect transistors (FETs) and their fabrication.
Integrated circuits which interface to analog inputs and outputs (I/Os) and perform specialized functions, such as controlling microelectromechanical systems (MEMS) modules, heaters, valves, relays and other applications, are often built using low cost fabrication process sequences. Photolithographic operations are typically the most costly and complex fabrication process steps involved in building an IC, so a common aspect of low cost fabrication process sequences is a simplified device architecture built with a minimal number of photolithographic steps. Components in ICs built on a simplified device architecture have limited complexity and are not capable of operating at high voltages, for example above 20 volts, so that IC design for specialized functions with high voltage I/Os involves a trade-off between performance and fabrication cost. Accordingly, there is a need for integrated circuits built with few photolithographic steps and capable of controlling higher voltage inputs and outputs.